Light-emitting diodes (LEDs) can be more effective if the LED package is adequately designed to effectively extract the light which is generated inside the LED under operating conditions. From the perspective of a device designer, effective light extraction can be a matter of improving the chances that light from the LED die is effectively guided so it can leave the LED package in the desired direction. A number of design features can influence the optical paths such as the orientation and the position of reflective interfaces and whether the type of reflection has a specular or diffuse nature. Moreover, refractive properties of elements of an LED package can affect the efficiency of the light extraction.
One of the problems associated with current LED packages occurs with those packages where there is a mounting edge or a seating shelf for a lens which covers an encapsulant-filled cavity. This configuration seals off the volume enclosing the encapsulant and can impair degassing. Thus bubbles of gas entrapped within the encapsulant can cause unwanted scattering of the light, causing deterioration of the light output of the package.
A further disadvantage of current LED packages is present in those packages where there is a mounting surface for the lens rather than a mounting edge. Due to the planar nature of the interface between the lens and the mounting surface, the encapsulant can easily be trapped within this interface, together with gas bubbles therein. This again can result in a deterioration of the light output of the package.
Therefore there is a need for a new lighting device package that overcomes some of the drawbacks of known designs.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.